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91.
Today, the surface imprinted polymers emerge in various fields as synthetic adsorbents gaining attention in a variety of application areas. In this study, Cu(II) ion surface imprinted poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA), cryogels were synthesized via modified two-step polymerization which is different from given in literature and the adsorption of Cu(II) ion from aqueous solution was investigated batch wise. In this respect, the method applied in this study is new in the literature despite heavy metal removal studies reported. The polyethyleneimine (PEI) molecule was used in polymeric structure as a ligand. The poly(HEMA-GMA) cryogels prepared was characterized via Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma optical emission spectrometry (ICP-OES), elemental analysis, scanning electron microscopy (SEM) and the micro-computed tomography (μCT). 相似文献
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93.
Three independent methods, (i) electrospray ionization mass spectrometry (ESI-MS), (ii) carrying out the complete protein preparation procedure required for protein gel electrophoresis (GE) including extraction, precipitation, washing, and desalting with subsequent microwave digestion of the produced protein fractions for metal content quantification, and (iii) ultrafiltration for separating protein-bound and unbound metal fractions, were employed to elucidate the influences of protein sample preparation and GE running conditions on metal-protein bindings. A treatment of the protein solution with acetone instead of trichloroacetic acid or ammonium sulfate for precipitate formation led to a strongly enhanced metal binding capacity. The desalting step of the resolubilized protein sample caused a metal loss between 10 and 35%. The omission of some extraction buffer additives led to a diminished metal binding capacity of protein fractions obtained from the sample preparation procedure for GE, whereas a tenside addition to the protein solution inhibited metal-protein bindings. The binding stoichiometry of Cu and Zn-protein complexes determined by ESI-MS was influenced by the type of the metal salt which was applied to the protein solution. A higher pH value of the sample solution promoted the metal ion complexation by the proteins. Ultrafiltration experiments revealed a higher Cu- and Zn-binding capacity of the model protein lysozyme in both resolubilization buffers for 1D- and 2D-GE compared to the protein extraction buffer. Strongly diminished metal binding capacities of lysozyme were recorded in the running buffer of 1D-GE and in the gel staining solutions. 相似文献
94.
采用场发射扫描电镜(FESEM)和X射线能谱仪(EDXS)对感应熔炼高锰硅(HMS)中的第二相条纹的形貌和成份进行了研究,发现第二相条纹平行贯穿整个高锰硅晶粒,其条纹宽度约30nm,间距在5-30μm内,成份为MnSi.通过高分辨透射电镜(HRTEM)观察到MnSi条纹为短程有序而长程无序的非晶形态.采用选区电子衍射(SAED)确定了高锰硅的晶体结构,结果表明所获得的高锰硅为单一的Mn4Si7相,未观察到高锰硅其它的非公度结构.透射电镜(TEM)结果表明,熔炼的高锰硅经过球磨和热压后产生了大量缺陷和应力畴,与热压之前的熔锭材料相比有明显差异. 相似文献
95.
以硝酸铈铵和尿素为反应物,γ-氨丙基三乙氧基硅烷(KH550)为助剂,通过沉淀反应制得了单晶菱形CeOHCO3片状物。然后将CeOHCO3在600℃空气气氛中灼烧获得了菱形CeO2。通过XRD和SEM对反应物中是否含有KH550助剂所得的产物进行了分析,结果发现只有含有KH550才能获得菱形CeOHCO3片状物,并且在灼烧过程中产物的形貌仍保持菱形。然后采用TEM对菱形CeOHCO3和CeO2进行了表征,结果发现CeOHCO3为单晶产物而灼烧后所得的CeO2为多晶产物。 相似文献
96.
Liquid phase hydrogenolysis of ethyl lactate to 1,2‐propanediol was performed over silica supporting cobalt catalysts prepared by two different methods: precipitation‐gel (PG) technique and deposition‐precipitation (DP) procedure. The cobalt species (Co3O4/cobalt phyllosilicate) present in the corresponding calcined PG and DP catalysts were different as a consequence of the preparation methods, and Co OH Co olation and Si O Co oxolation molecular mechanisms were employed to elucidate the chemical phenomena during the different preparation procedures. In addition, the texture (BET), reduction behavior (TPR and in‐situ XRD), surface dispersion and state of cobalt species (XPS), and catalytic performance differ greatly between the samples. Because of small particle size, high dispersion of cobalt species and facile reducibility, the Co/SiO2 catalyst prepared by precipitation‐gel method presented a much higher activity than the catalyst prepared by deposition‐precipitation method. Metallic cobalt is assumed to be the catalytically active site for the hydrogenolysis reaction according to the catalytic results of both cobalt samples reduced at different temperatures and the structure changes after reaction. 相似文献
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98.
The hydrocarbon plus fractions that comprise a significant portion of naturally occurring hydrocarbon fluids create major problems when determining the thermodynamic properties and the volumetric behavior of these fluids by equations of state. These problems arise due to the difficulty of properly characterizing the plus fractions (heavy ends). Proper characterization of the heavier components is important when cubic equations of state and/or solid formation thermodynamic models are used to describe complex phase behavior of reservoir fluids. The effect of heavy fractions characterization on thermodynamic modeling of wax precipitation has been investigated using different models including Won, Pan and proposed models. In order to characterize the plus fraction (heavier part) as a series of pseudocomponents, a probability model that expresses the mole fraction as a continuous function of the molecular weight has been used. The study has been conducted using several mixtures. Two different SCN (single carbon number), C7+ and C10+ were chosen. The Chosen SCN were distributed to multi-components of five, six, and/or ten using continuous function and Gaussian quadrature method. The results showed that the fractioning is required to be able to predict wax precipitation. Distribution of C10+ using a proper distribution function has shown improvement in predictions of WAT and the amount of wax deposited in comparison with the characterization of C7+ using semi-continuous approach. In predicting of WAT and the amount of wax build up the developed model showed superiority over the others. 相似文献
99.
Nfor BK Hylkema NN Wiedhaup KR Verhaert PD van der Wielen LA Ottens M 《Journal of chromatography. A》2011,1218(49):8958-8973
Salt-induced protein precipitation and hydrophobic interaction chromatography (HIC) are two widely used methods for protein purification. In this study, salt effects in protein precipitation and HIC were investigated for a broad combination of proteins, salts and HIC resins. Interrelation between the critical thermodynamic salting out parameters in both techniques was equally investigated. Protein precipitation data were obtained by a high-throughput technique employing 96-well microtitre plates and robotic liquid handling technology. For the same protein-salt combinations, isocratic HIC experiments were performed using two or three different commercially available stationary phases-Phenyl Sepharose low sub, Butyl Sepharose and Resource Phenyl. In general, similar salt effects and deviations from the lyotropic series were observed in both separation methods, for example, the reverse Hofmeister effect reported for lysozyme below its isoelectric point and at low salt concentrations. The salting out constant could be expressed in terms of the preferential interaction parameter in protein precipitation, showing that the former is, in effect, the net result of preferential interaction of a protein with water molecules and salt ions in its vicinity. However, no general quantitative interrelation was found between salting out parameters or the number of released water molecules in protein precipitation and HIC. In other words, protein solubility and HIC retention factor could not be quantitatively interrelated, although for some proteins, regular trends were observed across the different resins and salt types. 相似文献
100.